Countersunk holes are commonly used throughout industry where it is necessary or desirable to recess the head of a fastener, such as a screw or rivet. For example, countersunk holes are extensively employed in the aircraft industry, where rivets are used to attach an outer skin to frame members. In this latter mentioned application, it is particularly important that the top of the rivet be flush with the outer surface of the skin, otherwise non-flush rivets disturb the airflow over the skin, creating turbulence which adds to drag on the aircraft. Consequently, it is important that the tapered side walls of the hole countersink have a precise depth calculated so that the top of the rivet is flush with the skin surface.
In the past, forming a countersunk hole in aircraft applications was a two step, manual process that involved drilling a hole of the desired diameter in a first operation, and then countersinking the hole with a countersink tool in a second operation. Because two steps were required using two different tools, the process was time consuming. In addition, because the process was performed manually, consistent results depended in large part on the skill of the operator.
Accordingly, there is a need in the art for a countersink drill that overcomes the deficiencies of the prior art discussed above. The present invention is directed towards satisfying this need.